public abstract class GenericMatrix<E> {
  protected abstract E add(E o1, E o2);
  protected abstract E multiply(E o1, E o2);
  protected abstract E zero();

  public E[][] addMatrix(E[][] matrix1, E[][] matrix2) {
    if ((matrix1.length != matrix2.length) ||
        (matrix1[0].length != matrix2[0].length)) {
      throw new RuntimeException("The matrices do not have the same size");
    }

    E[][] result = (E[][])new Object[matrix1.length][matrix1[0].length];

    for (int i = 0; i < result.length; i++) {
      for (int j = 0; j < result[i].length; j++) {
        result[i][j] = add(matrix1[i][j], matrix2[i][j]);
      }
    }

    return result;
  }

  public E[][] multiplyMatrix(E[][] matrix1, E[][] matrix2) {
    if (matrix1[0].length != matrix2.length) {
      throw new RuntimeException("The matrices do not have compatible size");
    }

    E[][] result = (E[][])new Object[matrix1.length][matrix2[0].length];

    for (int i = 0; i < result.length; i++) {
      for (int j = 0; j < result[0].length; j++) {
        result[i][j] = zero();

        for (int k = 0; k < matrix1[0].length; k++) {
          result[i][j] = add(result[i][j], multiply(matrix1[i][k], matrix2[k][j]));
        }
      }
    }

    return result;
  }

  public static void printResult(Object[][] m1, Object[][] m2, Object[][] m3, char op) {
    for (int i = 0; i < m1.length; i++) {
      for (int j = 0; j < m1[0].length; j++) {
        System.out.print(" " + m1[i][j]);
      }

      if (i == m1.length / 2) {
        System.out.print("  " + op + "  ");
      } else {
        System.out.print("    ");
      }

      for (int j = 0; j < m2.length; j++) {
        System.out.print(" " + m2[i][j]);
      }

      if (i == m1.length / 2) {
        System.out.print("  =  ");
      } else {
        System.out.print("     ");
      }

      for (int j = 0; j < m3.length; j++) {
        System.out.print(m3[i][j] + " ");
      }

      System.out.println();
    }
  }
}
